Radio condenser coupling



1 632,878 June 21, 1927- BREMER RADIO CONDENSER COUPLING Filed May 24, 1926 nmumggn I, n 16 1m In 15 @IIIIIIIIHHIIIIIIMI' (A m Patented June 21, 1927;

' UNITED STATES HARQRY A. BREMER, OF CHICAGO, ILLINOIS.

RADIO connnnsnn COUPLING.

Application filed May 24, 1926. Serial No. 111,146.

In modern radio'receiver practice it is becoming necessary to couple a plurality of condenserstogether on one continuous operating shaft which may serve to rotate anywhere from two up to six or eight condensers. In order to produce such units with a single continuous operating shaft very great precision of manufacture is required. The obvious method. of course, is to build a solid base or frame casting, such as the bearing casting used in multiple cylinder gasoline motors, carefully machining all the bearings into accurate alignment. In such a construction, a perfectly true shaft is also required, since, any inaccuracy of alignment of the shaft journals would result in binding action of the shaft and would fail to give a smooth turning control. 7

Each condenser, together with its coil,

tube sockets, and other minor parts, constitutes a so-called stage of amplification. In manufacturing practice, it is desirable to build these stages up individually, so that each may be tested separately and brought up to certain electrical specifications and requirements before installationin the set, or to be sold individually for use by the home builder, who may thus purchase these stages and install two or more in any'desired combination.

One object of my invention is to provide a simple and inexpensive condenser coupling, which will permit the several stages to be made and tested with their independent condensers and readily coupled in any desired numbers either at the factory or by the user. Another object is to provide a construction which will obviate the necessity. above alluded to, of accurate machining of the shaft journals and bearings to procure perfectalignment, and will be self-adjusting to any slight inaccuracies in the set-up.

A further object is to provide a construction makin it possible to insulate the condenser sha t between stages which is often desirable; and another object is to provide a construction making it practicable to install the units on an ordinary baseboard or casting without the necessity of extensive machining of the casting or securing perfect ali ment of the several condenser shafts;

till other objects and attendant advan- 'tages, of the invention will be apparent to users of a paratus of this type and others skilled in tlie artfrom the following'detailed description, taken in connection with the accompanaying drawing wherein I have illustrated a simple embodiment of the principle of the invention in slightly differing forms, and in which- Fig. 1 is a top plan view showing a plurality of radio condensers disposed with their shafts eudto end and coupled for simultaneous rotary movement by means contemplated within the present invention;

F1g. 2 is a cross-section on the line 2--2 of Fig; 1;

Fig. 3 is a sectional detail on the line 33 of Fig. 2;

Fig. 4.- is a sectional detail similar toFig. 3, showing a modification; and v Fig. 5 is a top plan View, partly in sec t-lon, of one of the arms and its hub, show mg a means of insulating adjacent condensers when employing an arm coupling such as is shown in Fig. 4.

Referring to the drawings. A designates a baseboard on which are mounted in tandem a plurality of condensers B, C and D, herein shown as of the well-known type employing groups of alternating stationary and rotatable segment plates, the rotatable segment plates being fast on the condenser shafts b, c, d which, as shown, are arranged end to end and theoretically inaxial alignment. In actual practice, however, in the mounting of the several condensers on their support it is'a matter of considerable difficulty and expense to insureaccurate axial alignment of the several condenser shafts so that, if they are, rigidly coupled and operated by a single turning device, such as the knob K or a worm-gear transmission, on the panel end of one of the shaft sections, there is likely to ensue a. binding action of the shaft, making impossible a control of the knob.

My present.invent-ion provides a very simple, inexpensive and efiicient means for coupling adjacent ends of adjacent condenser shafts which insures simultaneous and equal smooth turning movements of the several shafts from the operating knob K without any binding of the shaft or uneven load on the knob; this coupling means, in the simple form herein shown, comprising opposed radial arms on the meeting ends of adjacent shafts with interengaging parts on said arms ada ted to have relative movement in a dial direction only to compensate for any smooth turning lack of exact axial alignment of the two shafts and their bearings.

Referring to the coupling of shafts b and c, secured on shaft 0 as by a set screw 10 is a hub 11, soldered or otherwise secured to .which is a radially projecting arm 12, preferably consisting of a thin strip of elastic sheet-metal. in which strip is secured a pin or stud 13. Similarly secured to the meeting end of the shaft 6 as by a set screw 14 is a hub 15, soldered or otherwise secured to which is a mating arm 16 lying opposite the arm 12 and formed with a radial slot 17 (Fig. 2) into which the stud 13 projects. y reference to Fig. 2 it will be observed that the slot 17 is somewhat longerthan the width of the stud 13 in the direction ofthe slot, so that the pin may have relative movement lengthwise of the slot when the shaft 6 is turned, to thereby prevent binding in the bearings of the shafts b and c in case said bearings are slightly out of line. The stud 13 snugly engages with the longitudinal edges of the slot 17, sothat there is no lost motion or play in a circumferential direction between the stud and the slot. To insure this latter, the stud 13 is preferably of rectangu lar cross-section, and is tapered on those sides which en age with the edges of the slot, as clearly shown in Fig. 3; and the arms 12 and 16 are formed with a spring urge toward each other, when mounted on then respective shafts, so that the longitudinal edges of the slot 17 always tend to hug the tapered sides of the pin 13.

With his construction of connection between the two arms, insulation between the indicated in Figs. 4 and 5; wherein, in lieu of the stud 13 attached to one of the arms, the latter may be cut and punched to provide'a pair of oppositely inclined lugs or t-angs 18 that engage with the slot 17 in the manner already described. When employing this connection between the arms, insulation between two condensers may be obtained for example as shown in Fig. 5, wherein the arm the invention as embodied in a means for simultaneously rotating a plurality of condensers, it is manifest that the same system might-be advantageously employed for simultaneously rotating inductance coils as well as, or instead of, condensers; since a receiving set may be tuned by rotating variable inductances.

The manner in which the described invention secures the stated purposes and objects thereof will bereadily apparent from the foregoing description. The main advantage of the invention resides in its avoidance of the necessity of accurately aligned shaft bearings, which are usually formed on a single base casting of suitable length to accommodate the entire series of devices to be coupled, and of the necessity of providing a single continuous shaft, or its equivalent. Manifestly, the described construction is much cheaper than a unit construction, is equally smooth and efficient in operation, and has the further added advantages of enabling the several so-called sta es to be independently erected and 'teste before assembly in the receiving set.

1. In radio receiving apparatus, a lurality of condensers arranged with t eir shafts end to end, opposed arms fast on adjacent ends of ad'acent shafts, one of said arms having a ra ial slot, and a pro'ection on the other arm havin tapered si es engaged with the longitu inal ed es of said slot, said projection beingycapa le of play lengthwise of said slot. I

2. A specific form of claim 1, wherein said arms are spring-pressed toward each .0'.-'18I' to prevent play between said rojection and said slot in a circumferential irection.

HARRY- A. BREMER. 

